I picked up one of them the other day, at a yard sale. Sitting beside a saw set. $0.25 each. Couldn’t hurt to pick up both? Now the question is: WHAT is a saw jointer? I know in involves a file, and a saw blade. How does one set up one of these?

A photo of both of these tools. The saw set I will clean up. The jointer? Don’t know what I’m doing, does it hold a file? If so, HOW? No brand name of either of these “jewels”. A simple looking thing, just a couple moving parts.

-- A Planer? I'M the planer, this is what I use

3 replies so far

The number and variety of jointers are considerable, but the principle is the same for all. They hold a file in such a way that the jointer can be run over the saw teeth to ensure the teeth all lie on the circle of the saw. There are short and long jointers. The short jointer, generally part of a combination saw tool, is by far the more common.

Jointer combination saw tools

Short Jointer

To use the short jointer, insert the file so it rests flat on the file supports (lugs) and adjust the screw so the file bends to conform to the circle of the saw. Make sure the surface of the file is square with the guide rails on the body of the jointer. The file may be warped or improperly seated on the supports. Insert the file so it runs in the normal filing direction. (If a file is used backward, its life will be severely shortened.) Because a new file often will cut faster than desired, a wornout 7- or 8-inch special crosscut file with the tang broken off works well.

Place the jointer on one end of the saw. Holding the jointer so the file rests on the cutter teeth, run the jointer the length of the saw using uniform downward pressure. This is important if the circle of the saw is to be maintained. It is also important to hold the guide rails on the body of the jointer in contact with the side of the saw at all times to ensure that the file is square to the saw.

After the jointer has been run the length of the saw, look at the teeth. If each tip has a shiny spot where the file has just touched it, jointing is complete. If some teeth are so short they weren’t touched, repeat the process until all teeth show the mark of the file. If a tooth has been chipped or broken so it is much shorter than the rest, don’t worry about it. No sense jointing the life out of a saw to make it perfect.

Jointing the cutter teeth

Long Jointer

If a long jointer is available, it achieves superior results and guarantees a round saw when used properly. A saw that has deviations from its arc (bumps or troughs) won’t saw smoothly. The long jointer operates on the principle that three points in a plane uniquely define a circle (or arc), or that there is only one circle that will simultaneously pass through three given points in a plane.

The long jointer has two “shoes” about 12 inches apart with a file mounted between them. The file can be moved up and down relative to the two shoes. Whether the shoes or the file moves is immaterial. The two shoes and the file constitute the three points that define a circle. Only two long jointers were ever commercially manufactured. One, a Gibbs jointer, was marketed by Simonds Saw and Steel Co., and the other by E. C. Atkins and Co. The shoes on the Gibbs jointer move and the file on the Atkins moves.

As with the short jointer, it is a good idea to make sure the file is square with the guide rails on the body of the jointer. This can be checked with a small square.

Jointing a saw with a long jointer

With the saw in a stable position, preferably in a saw vise, place the jointer about in the center of the saw. Adjust the jointer so that both shoes and the file contact the saw and tighten the adjusting nuts. By moving the jointer along the saw and observing whether the jointer rocks on the file or has space between the file and the teeth, the high and low places can be observed easily. When the high and low spots are found, adjust the jointer so the file clears all but the higher spots. This is done by placing the jointer on a high spot and adjusting it so the file and shoes will contact the saw. These are important steps. If the initial jointer adjustment were made with the file over a relatively low spot and the saw jointed with that setting, it would be impossible to get the saw into round without taking excess material off the center teeth.

With the jointer adjusted on the saw, pass it lightly and evenly from one end of the saw to the other. The very end teeth should be jointed in this process. This means dropping one shoe or the other off the end of the saw to run the file over the end teeth. The file will cut the tips off the high teeth. If—as is often the case with really worn saws—the file will not make contact toward the end of the saw, the end teeth are too long. This can be corrected by jointing the ends more severely than the center of the saw. If the teeth are particularly long, a lot of time can be saved by cutting these teeth down with a handheld file, checking your progress periodically with the jointer.

As with the short jointer, the saw should only be jointed until all the teeth have been marked by the file (except extremely short or broken teeth). The less metal taken off the teeth, the less work the filer must do later in pointing up the teeth, and the longer the saw will last.

The end teeth of a solid-ended saw cannot be effectively jointed with a long jointer unless the solid section is filed to or below the circle of the saw.

It is possible to cut the solid end off a saw and repunch the holes for the handles.